Question

Tìm max

B=-x^2+8x-1

Answer 1

\(B=-x^2+8x-1=-\left(x^2-2.x.4+4^2\right)+15=-\left(x-4\right)^2+15\\ Vì:\left(x-4\right)^2\ge0\forall x\in R\\ \Rightarrow15-\left(x-4\right)^2\le15\forall x\in R\\ Vậy:max_B=15.khi.x=4\)

Answer 2

MAX_B = 15 khi x = 4